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Do lie detectors...lie?

We humans would like to think we have a firm grasp on the truth. Unfortunately we do only slightly better than chance, about 55% of the time we are correct, when it comes to deciphering whether or not someone is telling the truth. Perhaps even as you are reading this, you are thinking to yourselves, "This can't be right, I'm excellent at deciding whether or not someone is lying!" Unfortunately though, "there's typically little or no correlation between people's confidence in their ability to detect lies and their accuracy" (Ekman, 2001). Have no fear; the polygraph test is here to save the day! Or is it?

The polygraph test, more commonly referred to as the lie detector, is supposed to be able to tell whether or not people are lying. It's an excellent concept that in the end falls short. By gauging levels of arousal, such as blood pressure, respiration, and skin conductance, it ends up doing better than chance at detecting lies. Better than chance is alright, yet it often times convicts innocent people, and occasionally will let guilty people go free. In fact, an individual can be trained in less than half an hour on how to "defeat" the lie detector test. Results show that half or more of these people end up actually being able to deceive the polygraph test. Perhaps we will never be able to know 100% whether or not someone is telling the truth or lying. Were you surprised by how poorly people are able to detect lies, or perhaps by the fact that the lie detector isn't the fail proof method that pop culture makes it out to be?

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5 Comments

I think this post brings up a very good point. I have always been one to not believe in things, and the lie detector test is one of them. I could never understand why a machine could determine someone's life. If someone gets convicted of something, a lot of people pushed towards using polygraph test. Since polygraph tests are better than chance, I think they could be used, if someone feels like it is necessary, to help them come to a conclusion. However, I feel like the results should not be weighted very heavily because there are ways to beat the system, and there are ways to get screwed over from it. I think people too easily come to conclusions, and a lot of innocent people get convicted because of it. Our society as a whole needs to start gathering more, clear/strong evidence before deciding someone's life.

This is one of the more interesting post that I have read this year. Lie detectors are only a little better then chance at correctly telling if we are yelling or not. Whoever initially thought that you could use this to convict someone deserves some time in jail. The polygraph test bases decisions on arousal or other factors that naturally change based on the question being asked. I learned a few things from this blog but my favorite has to be how to trick the polygraph test. I want to be able to learn that trick.

I am also one who has always thought of the lie detector to be correct at detecting lies or not. I figured there was a chance that it could be incorrect sometimes, but i never thought that it would be possible to learn hows to "defeat" the lie detector, and in as fast as 30 minutes. If it is that easy to learn to defeat the lie detector i cant believe they would use it as a means to determine whether or not someone is convicted. I am very surprised by this.

There are a number of TV series about detecting crimes such as “Criminal minds (2005- )” and “Mentalist (2008- )”. When watching these shows, it isn’t hard to see FBI agents or detectives using lie detectors to find out whether the suspect is telling the truth. But as you mentioned, I remember in one of the series a retired soldier managed to deceive the polygraph test. I don’t know if detectives or the prosecution still use lie detectors in America, but as more people know how lie detectors work and also how it can be deceived, the practicality of polygraph tests seems to be questioned. How else could we know the suspect is telling the truth or not?

This post is indeed very interesting. I think that the reason lies exist in the first place is because as humans we are so bad at detecting lies. If we could effectively (better than 90% of the time) identify when someone was lying, then I believe lying would become an obsolete tradition. It only exists still because it is so easy to get away with. Another aspect of the whole lying talk that comes to my mind is whether sarcasm is considered lying or not. Sarcasm can often times be misleading and not the truth, so does that make it a lie? What do you think?